High-resolution timer

Hello. I have such a problem: I need to measure time precisely, acceptable inaccuracy is about 1-2 msec. I use Qt SDK 1.1 on Windows XP. I tried QTimer, clock(), chrono, I also tried to increase application priority to Real time but inaccuracy always is 5 msec (or 15, I'm not sure about it). Could anybody please tell me what's the problem and how to deal with it?

@AntonZelenin
Are you perchance using Qt 4, as the timer types are introduced in Qt 5?
If that's so (which is very probable) I advise to switch to Qt 5. Qt 4 has been marked not advised for new development.

And QElapsedTimer gave me only 10 msec accuracy

This would ultimately depend on the accuracy the OS can provide.

Kind regards.

Even if we accept, as the basic tenet of true democracy, that one moron is equal to one genius, is it necessary to go a further step and hold that two morons are better than one genius?

I have a Qt application that was build with Qt 5.6 and sadly (or to my surprise) I know of nearly a dozen users that use it on Windows XP without any issues.
Of course this might depend on the features and modules that you are using. So just to be sure: I am not saying you that your application will definitely work on Windows XP if you move to Qt 5. I'm just saying that my application(s) appear to work for Windows XP users.